"I make music, but I don't do voice-overs every day of the week, and their characters are so awesomely convincing and sincere and wild and funny, I had to remind myself constantly of the sincerity of the humour.

The episode will include plenty of costume changes and a girl-on-girl kiss with wife and mother Marge.

"I would say this is one of the coolest things I've ever done. My dad's probably going to do 80 backflips when the episode comes out," she said.